377 results found
Shah PL, Kemp SV, Newton RC, et al., 2016, Clinical Correlation between Real-Time Endocytoscopy, Confocal Endomicroscopy, and Histopathology in the Central Airways, RESPIRATION, Vol: 93, Pages: 51-57, ISSN: 0025-7931
Clancy NT, Saso S, Stoyanov D, et al., 2016, Multispectral imaging of organ viability during uterine transplantation surgery in rabbits and sheep., Journal of Biomedical Optics, Vol: 21, ISSN: 1083-3668
Uterine transplantation surgery (UTx) has been proposed as a treatment for permanent absolute uterine factor infertility (AUFI) in the case of the congenital absence or surgical removal of the uterus. Successful surgical attachment of the organ and its associated vasculature is essential for the organ’s reperfusion and long-term viability. Spectral imaging techniques have demonstrated the potential for the measurement of hemodynamics in medical applications. These involve the measurement of reflectance spectra by acquiring images of the tissue in different wavebands. Measures of tissue constituents at each pixel can then be extracted from these spectra through modeling of the light–tissue interaction. A multispectral imaging (MSI) laparoscope was used in sheep and rabbit UTx models to study short- and long-term changes in oxygen saturation following surgery. The whole organ was imaged in the donor and recipient animals in parallel with point measurements from a pulse oximeter. Imaging results confirmed the re-establishment of adequate perfusion in the transplanted organ after surgery. Cornual oxygenation trends measured with MSI are consistent with pulse oximeter readings, showing decreased StO2 immediately after anastomosis of the blood vessels. Long-term results show recovery of StO2 to preoperative levels.
Lin J, Clancy NT, Sun X, et al., Hybrid Tissue Surface Hyperspectral imaging and Shape Recovery, Hyperspectral Imaging & Applications Conference
Lin J, Clancy NT, Sun X, et al., Probe-based Rapid Hybrid Hyperspectral and Tissue Surface Imaging Aided by Fully Convolutional Networks, Medical Image Computing and Computer Assisted Intervention (MICCAI)
Lin J, Clancy NT, Sun X, et al., 2016, Probe-based rapid hybrid hyperspectral and tissue surface imaging aided by fully convolutional networks, Medical Image Computing and Computer-Assisted Intervention -- MICCAI 2016, Publisher: Springer International Publishing AG, Pages: 414-422, ISSN: 0302-9743
Tissue surface shape and reflectance spectra provide rich intraoperative information useful in surgical guidance. We propose a hybrid system which displays an endoscopic image with a fast joint inspection of tissue surface shape using structured light (SL) and hyperspectral imaging (HSI). For SL a miniature fibre probe is used to project a coloured spot pattern onto the tissue surface. In HSI mode standard endoscopic illumination is used,with the fibre probe collecting reflected light and encoding the spatial information into a linear format that can be imaged onto the slit of a spectrograph. Correspondence between the arrangement of fibres at the distal and proximal ends of the bundle was found using spectral encoding. Then during pattern decoding,a fully convolutional network (FCN) was used for spot detection,followed by a matching propagation algorithm for spot identification. This method enabled fast reconstruction (12 frames per second) using a GPU. The hyperspectral image was combined with the white light image and the reconstructed surface,showing the spectral information of different areas. Validation of this system using phantom and ex vivo experiments has been demonstrated.
Qi J, Elson DS, Polarimetric rigid endoscopes for tissue imaging, 2nd Workshop of the European Industrial Doctorate
Elson DS, Endoscopic image-guided thermal therapy using targeted near infrared fluorescent gold nanorods (invited), SPIE Optics+Photonics
Avila-Rencoret F, Oude Vrielink T, Elson DS, et al., EndoSDR: Concurrent Endoscopic Screening, Diagnosis, and Removal of GI cancers (prize winner), Business Engineering and Surgical Technologies Innovation Symposium (BEST)
Jones G, Clancy NT, Arridge S, et al., Inference of Tissue Haemoglobin Concentration From Stereo RGB, 7th International Conference on Medical Imaging and Augmented Reality
Singh M, Nabavi E, Zhou Y, et al., 2016, Application of Gold Nanorods in Cancer Theranostics, International Surgical Congress of the Association-of-Surgeons-of-Great-Britain-and-Ireland, Publisher: WILEY-BLACKWELL, Pages: 16-16, ISSN: 0007-1323
Avila Rencoret FB, Elson D, Mylonas G, A Robotic Hyperspectral Scanning Framework for Endoscopy, CRAS - Workshop on Computer/Robot Assisted Surgery
Gastrointestinal (GI) endoscopy is the gold-standard procedure for detection and treatment of dysplastic lesions and early stage GI cancers. Despite its proven effectiveness, its sensitivity remains suboptimal due to the subjective nature of the examination, which is substantially reliant on human-operator skills. For bowel cancer, colonoscopy can miss up to 22% of dysplastic lesions, with even higher miss rates for small (<5 mm diameter) and flat lesions. We propose a robotic hyperspectral (HS) scanning framework that aims to improve the sensitivity of GI endoscopy by automated scanning and real-time classification of wide tissue areas based on their HS features. A “hot-spot” map is generated to highlight dysplastic or cancerous lesions for further scrutiny or concurrent resection. The device works as an add-on accessory to any conventional endoscope, and to our knowledge, is the first of its kind. This paper focuses on characterising its optical resolution on rigid and deformable colon phantoms. We report for the first time 2D and 3D wide-area reconstruction of endoscopic HS data with sub-millimetre optical resolution. The current setup, compatible with the anatomical dimensions of the colon, could allow the identification of flat and small pre-cancerous lesions that are currently missed. The proposed framework will lay the foundations towards the next generation of augmented reality endoscopy while increasing its sensitivity and specificity.
Wirkert S, Kenngott H, Mayer B, et al., Robust near real-time estimation of physiological parameters from megapixel multispectral images with inverse Monte Carlo and random forest regression, Information Processing in Comupter Aided Intervention
Saso S, Jones B, Clancy N, et al., 2016, Imaging of organ viability during deep pelvic surgery: The use of biomedical photonics to assess uterine perfusion and vessel integrity in uterine transplantation models, Publisher: Wiley, Pages: 20-20, ISSN: 1471-0528
Singh M, Nabavi E, Zhou Y, et al., Application of Gold Nanorods in Cancer Theranostics (plenary presentation winner), Society for Surgery of the Alimentary Tract Annual Meeting, 31st Annual SSAT Residents and Fellows Research Conference
Qi J, Elson D, 2016, A high definition Mueller polarimetric endoscope for tissue characterisation, Scientific Reports, Vol: 6, ISSN: 2045-2322
The contrast mechanism of medical endoscopy is mainly based on metrics of optical intensity andwavelength. As another fundamental property of light, polarization can not only reveal tissuescattering and absorption information from a different perspective, but can also provide insight intodirectional tissue birefringence properties to monitor pathological changes in collagen and elastin.Here we demonstrate a low cost wide field high definition Mueller polarimetric endoscope with minimalalterations to a rigid endoscope. We show that this novel endoscopic imaging modality is able toprovide a number of image contrast mechanisms besides traditional unpolarized radiation intensity,including linear depolarization, circular depolarization, cross-polarization, directional birefringence anddichroism. This enhances tissue features of interest, and additionally reveals tissue micro-structure andcomposition, which is of central importance for tissue diagnosis and image guidance for surgery. Thepotential applications of the Mueller polarimetric endoscope include wide field early epithelial cancerdiagnosis, surgical margin detection and energy-based tissue fusion monitoring, and could furtherbenefit a wide range of endoscopic investigations through intra-operative guidance.
Elson DS, Surgical endoscopy, vision and bio-photonics, Royal Society International Scientific Seminar: Imaging in Graphics, Vision and Beyond
Wirkert SJ, Kenngott H, Mayer B, et al., 2016, Robust near real-time estimation of physiological parameters from megapixel multispectral images with inverse Monte Carlo and random forest regression, International Journal of Computer Assisted Radiology and Surgery, Vol: 11, Pages: 909-917, ISSN: 1861-6410
PURPOSE: Multispectral imaging can provide reflectance measurements at multiple spectral bands for each image pixel. These measurements can be used for estimation of important physiological parameters, such as oxygenation, which can provide indicators for the success of surgical treatment or the presence of abnormal tissue. The goal of this work was to develop a method to estimate physiological parameters in an accurate and rapid manner suited for modern high-resolution laparoscopic images. METHODS: While previous methods for oxygenation estimation are based on either simple linear methods or complex model-based approaches exclusively suited for off-line processing, we propose a new approach that combines the high accuracy of model-based approaches with the speed and robustness of modern machine learning methods. Our concept is based on training random forest regressors using reflectance spectra generated with Monte Carlo simulations. RESULTS: According to extensive in silico and in vivo experiments, the method features higher accuracy and robustness than state-of-the-art online methods and is orders of magnitude faster than other nonlinear regression based methods. CONCLUSION: Our current implementation allows for near real-time oxygenation estimation from megapixel multispectral images and is thus well suited for online tissue analysis.
Clancy NT, Teare J, Hanna GB, et al., Flexible Multimode Endoscope for Tissue Reflectance and Autofluorescence Hyperspectral Imaging, OSA Topical Meetings, Biomedical Optics
Elson DS, Application of Targeted Fluorescent Gold Nanorods for Image Guided Cancer Thermal Therapy (invited), OSA Topical Meetings, Biomedical Optics
Zhang Y, Wirkert SJ, Iszatt J, et al., 2016, Tissue classification for laparoscopic image understanding based on multispectral texture analysis, Conference on SPIE Image-Guided Procedures, Robotic Interventions, and Modeling, Publisher: Society of Photo-optical Instrumentation Engineers (SPIE), ISSN: 1996-756X
Intra-operative tissue classification is one of the prerequisites for providing context-aware visualization in computer-assisted minimally invasive surgeries. As many anatomical structures are difficult to differentiate in conventional RGB medical images, we propose a classification method based on multispectral image patches. In a comprehensive ex vivo study we show (1) that multispectral imaging data is superior to RGB data for organ tissue classification when used in conjunction with widely applied feature descriptors and (2) that combining the tissue texture with the reflectance spectrum improves the classification performance. Multispectral tissue analysis could thus evolve as a key enabling technique in computer-assisted laparoscopy.
Elson DS, Singh M, Nabavi E, et al., Application of Gold Nanorods in Cancer Theranostics, Association of Surgeons in Training
Thompson AJ, Koziej L, Williams H, et al., 2016, Towards optical fibre based Raman spectroscopy for the detection of surgical site infection, BiOS, SPIE Photonics West, Publisher: SPIE
Surgical site infections (SSIs) are common post-surgical complications that remain significant clinical problems, as they are associated with substantial mortality and morbidity. As such, there is significant interest in the development of minimally invasive techniques that permit early detection of SSIs. To this end, we are applying a compact, clinically deployable Raman spectrometer coupled to an optical fibre probe to the study of bacteria, with the long term goal of using Raman spectroscopy to detect infection in vivo. Our system comprises a 785 nm laser diode for excitation and a commercial (Ocean Optics, Inc.) Raman spectrometer for detection. Here we discuss the design, optimisation and validation of this system, and describe our first experiences interrogating bacterial cells (Escherichia coli) in vitro. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Singh M, Harris-Birtill DCC, Zhou Y, et al., 2016, Application of Gold Nanorods for Photothermal Therapy in Ex Vivo Human Oesophagogastric Adenocarcinoma, Journal of Biomedical Nanotechnology, Vol: 12, Pages: 481-490, ISSN: 1550-7041
Gold nanoparticles are chemically fabricated and tuned to strongly absorb near infrared (NIR) light, enabling deep optical penetration and therapy within human tissues, where sufficient heating induces tumour necrosis. In our studies we aim to establish the optimal gold nanorod (GNR) concentration and laser power for inducing hyperthermic effects in tissues and test this photothermal effect on ex vivo human oesophagogastric adenocarcinoma. The ideal GNR concentration and NIR laser power that would elicit sufficient hyperthermia for tumour necrosis was pre-determined on porcine oesophageal tissues. Human ex vivo oesophageal and gastric adenocarcinoma tissues were incubated with GNR solutions and a GNR-free control solution with corresponding healthy tissues for comparison, then irradiated with NIR light for 10 minutes. Temperature rise was found to vary linearly with both the concentration of GNRs and the laser power. Human ex vivo oesophageal and gastric tissues consistently demonstrated a significant temperature rise when incubated in an optimally concentrated GNR solution (3 × 1010 GNRs/ml) prior to NIR irradiation delivered at an optimal power (2 W/cm2). A mean temperature rise of 27 °C was observed in tissues incubated with GNRs, whereas only a modest 2 °C rise in tissues not exposed to any GNRs. This study evaluates the photothermal effects of GNRs on oesophagogastric tissue examines their application in the minimally invasive therapeutics of oesophageal and gastric adenocarcinomas. This could potentially be an effective method of clinically inducing irreversible oesophagogastric tumour photodestruction, with minimal collateral damage expected in (healthy) tissues free from GNRs.
Nabavi E, Singh M, Zhou Y, et al., 2016, Preliminary studies of fluorescence image-guided photothermal therapy of human oesophageal adenocarcinoma in vivo using multifunctional gold nanorods, Conference on Optical Methods for Tumor Treatment and Detection - Mechanisms and Techniques in Photodynamic Therapy XXV, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
We present a preliminary in vivo study of fluorescence imaging and photothermal therapy (PTT) of human oesophageal adenocarcinoma using multi-functionalised gold nanorods (GNRs). After establishing tumour xenograft in mouse functionalised GNRs were administrated intravenously (IV). Fluorescence imaging was performed to detect the tumour area. The intensity of the fluorescence signal varied significantly across the tumour site and surrounding tissues. PTT was then performed using a 808 nm continuous wave diode laser to irradiate the tumour for 3 minutes, inducing a temperature rise of ~44°C, which photothermally ablated the tumour.
Song L, Zhou Z, Wang X, et al., 2016, Simulation of speckle patterns with pre-defined correlation distributions, Biomedical Optics Express, Vol: 7, Pages: 798-809, ISSN: 2156-7085
We put forward a method to easily generate a single or a sequence of fully developed speckle patterns with pre-defined correlation distribution by utilizing the principle of coherent imaging. The few-to-one mapping between the input correlation matrix and the correlation distribution between simulated speckle patterns is realized and there is a simple square relationship between the values of these two correlation coefficient sets. This method is demonstrated both theoretically and experimentally. The square relationship enables easy conversion from any desired correlation distribution. Since the input correlation distribution can be defined by a digital matrix or a gray-scale image acquired experimentally, this method provides a convenient way to simulate real speckle-related experiments and to evaluate data processing techniques.
Qi J, Elson DS, A high definition Mueller polarimetric endoscope for tissue characterisation, BIOS - Advanced Biomedical and Clinical Diagnostic and Surgical Guidance Systems XIV
Lin JIANYU, Clancy NT, Sun X, et al., Probe-based Rapid Hybrid Hyperspectral and Tissue Surface Imaging Aided by Fully Convolutional Networks, Medical Image Computing and Computer Assisted Intervention (MICCAI)
Qi J, Elson D, Polarimetric rigid endoscopes for tissue imaging, 2nd Workshop of the European Industrial Doctorate
Qi J, Elson D, A high definition Mueller polarimetric endoscope for tissue characterisation, BIOS - Advanced Biomedical and Clinical Diagnostic and Surgical Guidance Systems XIV
Singh M, Nabavi E, Zhou Y, et al., Application of Gold Nanorods in Cancer Theranostics, European Association for Endoscopic Surgery (EAES)
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